The technology disclosed in the present specification relates to a wireless communication apparatus and electronic equipment transmitting and receiving radio wave signals, and specifically relates to a wireless communication apparatus and electronic equipment effectively utilizing spatial radio waves while transmitting and receiving the radio wave signals.
Various wireless transmission systems in which relatively high frequency bandwidths from hundreds MHz to several GHz are used for wireless transmission spread in recent years. For example, wireless LAN (Local Area Network) systems using the 2 GHz band, 5 GHz band or the like, wireless communication devices using from the 700 MHz band to the 2 GHz band for LTE (Long Term Evolution) or 3G communication systems, and electronic equipment loading wireless communication functions are developed and put into practical use.
Moreover, it is widely known that arrangement of a plurality of antennas attains diversity effects such as suppression of phasing due to multiple waves. For example, a transmitting and receiving antenna along with radiation diversity is proposed which includes first and second radiation elements connected to a transmitting and receiving circuit of electromagnetic signals via a network of power supplying lines at least on a substrate (for example, see National Publication of International Patent Application No. 2009-514292).
On the other hand, companies are starting to intensively develop applications of energy harvesting. For example, sensors or controllers whose power consumption is low can be driven using environmental energy not by the commercial power supply or batteries. Also in the field of communication, utilization of spatial radio waves is a task to be achieved as part of environmental power generation.
Power sources in the environmental power generation can include, for example, sunlight, vibration, heat, environmental electromagnetic waves. Some wireless communication devices and wireless communication systems using the environmental power generation are proposed (for example, see Japanese Patent Application Publication No. 2005-182643; Japanese Patent Application Publication No. 2004-355164; and Japanese Patent Application Publication No. 2002-118480). Moreover, an energy harvesting circuit is proposed in which an antenna receives energy in space and acquires part of it (for example, see National Publication of International Patent Application No. 2005-536150).
However, electric power radiated from electronic equipment is usually wasted without being used in fact. Meanwhile, radio waves from communication destination instruments and/or peripheral environments are received by an antenna to be rectified and recovered generally. In case that the antenna is shared by wireless communication and harvesting, whether the antenna can be used for the harvesting varies in accordance with a communication state, usage of the communication instrument and the like, whereas few technologies dynamically controlling the use of the antenna have been proposed.